JP2019201352A - Radio communication system, relay communication device, and communication control method - Google Patents

Abstract

To reduce the complexity of setting work of information change between a master base station and a secondary base station.SOLUTION: A SeNB generates first identification information identifying a radio access network on the basis of system information notified from a relay communication device to wirelessly transmit it to a UE, and notifies an MeNB of second identification information identifying a radio resource whose use is permitted via the relay communication device. The MeNB sets the first identification information on the SeNB to a signal destined to the SeNB selected from the SeNB of the first identification information received from the UE, sets the second identification information on the selected SeNB to a signal destined to the UE, and transmits it to the relay communication device. The relay communication device transfers the signal received from the master base station to the SeNB corresponding to the first identification information or second identification information set to the signal. The SeNB wirelessly transmits the signal destined to the UE transferred from the relay communication device.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a wireless communication system, a relay communication apparatus, and a communication control method.

  3GPP (3rd Generation Partnership Project) standard of mobile radio communication system In LTE (Long Term Evolution)-Advanced, UE (User Equipment) connects to two base stations and communicates at the same time (Dual Connectivity: DC) Is defined (see, for example, p. 49-53 of Non-Patent Document 1). A UE corresponding to the DC function can be simultaneously connected to a plurality of cells formed by two physically separated eNBs (evolved Node B). Therefore, it is possible to widen the downstream communication (meaning data transmission from the base station to the terminal) by carrier aggregation at a plurality of radio frequencies, and an increase in throughput can be expected.

  Non-Patent Document 1 defines two methods for transferring downlink user data to UE in DC. In the first scheme, an S-GW (Serving Gateway) of the core network divides user data distributed to the UE toward a master base station (Master eNB: MeNB) and a secondary base station (Secondary eNB: SeNB). . In the second scheme, the S-GW transfers all user data to the MeNB, and the MeNB divides user data for the SeNB.

  When using the second method, the MeNB transfers the amount of downlink user data for the UE to be transmitted using its own radio resource and the SeNB via the X2-IF line, and causes the SeNB to wirelessly transmit. The amount of downlink user data for the UE can be appropriately distributed. X2-IF is an interface that connects eNBs.

  FIG. 19 is a diagram illustrating an example of a network configuration of a wireless communication system that performs DC by a MeNB and a plurality of SeNBs. The MeNB 91 shown in the figure is connected to a plurality of subordinate SeNBs 92-1 to 92-3 via X2-IFs 93-1 to 93-3. In general, the MeNB 91 forms a wide coverage 10 at a radio frequency of 2 GHz or less. On the other hand, each of the SeNBs 92-1 to 92-3 forms a narrower coverage 20-1 to 20-3 than the MeNB 91 by using a frequency (for example, a radio frequency of 3.5 GHz or more) different from that of the MeNB 91.

  If the UE 94 having the DC function is in a position where the coverage 10 of the MeNB 91 and the coverage 20-3 of the SeNB 92-3 overlap, the UE 94 uses the radio band of the MeNB 91 and the radio band of the SeNB 92-3, respectively. Can be received.

  As a condition for the MeNB 91 and SeNBs 92-1 to 92-3 to communicate via the X2-IFs 93-1 to 93-3, the destinations (for example, IP addresses) that can be distinguished from each other in the TNL (Transport Network Layer) are grasped. It is a premise to do.

3GPP TS 36.300 version 13.9.0 Release 13, October 2017, p.38-39, p.49-53

  Non-Patent Document 1 does not stipulate how the MeNB and SeNB know each other's destination in the TNL. As a general method, a method of assigning and setting destinations in advance to the MeNB and SeNB can be considered. Moreover, the network configuration which employ | adopted X2 GW is described by p.38-39 of a nonpatent literature 1, In this network configuration, several HeNB and eNB mutually communicate. Therefore, it is conceivable that the destination (combination of IP address and Global eNB ID) in TNL is set in advance in X2 GW and eNB.

  As described above, usually, SeNB has a narrower coverage than MeNB. Therefore, in order to increase the area where DC is performed, it is necessary to install a large number of SeNBs. However, when the network configuration including the X2-IF between the MeNB and SeNB is changed due to the addition or removal of the SeNB, it is necessary to reset the destination in the TNL between the eNBs. For example, in order to accommodate user traffic that increases during a temporary event period, when the SeNB is added before the event starts and the added SeNB is removed after the event ends, the destination information is changed in the MeNB and multiple SeNBs. There must be. From the viewpoint of network construction and operation, each change operation is inefficient.

  Furthermore, the network operator responsible for installing and operating the MeNB may be different from the network operator responsible for installing and operating the SeNB. For example, the SeNB operator lends only SeNB radio resources to the MeNB operator, and provides a radio communication service to the UE by a DC technique. In this case, there is a problem that work adjustments for sharing destinations (network configurations) in TNLs among different operators increase.

  In view of the above circumstances, an object of the present invention is to provide a radio communication system, a relay communication apparatus, and a communication control method that can reduce the complexity of setting information change between a master base station and a secondary base station. Yes.

  One aspect of the present invention is a wireless communication system including a master base station, one or more secondary base stations, and a relay communication device that relays communication between the master base station and the secondary base station, The relay communication device includes a destination control unit that notifies the secondary base station of system information used for generating first identification information that identifies a radio access network used by the secondary base station for radio communication with a terminal; A process of notifying the master base station of second identification information for specifying a radio resource permitted to be used by the secondary base station, and a signal received from the master base station, the first identification information set in the signal Or a transfer path control unit that performs a process of transferring to the secondary base station according to the second identification information, and the secondary base station A first identification information generating unit that generates the first identification information based on the system information notified from the communication device, and the second identification information of the radio resource that is permitted to be used, via the relay communication device. A second identification information notification section for notifying the master base station, and a radio access communication function for wirelessly transmitting the signal set with the first identification information and the signal addressed to the terminal transferred from the relay communication device to the terminal The master base station selects the secondary base station that communicates with the terminal from the secondary base station of the first identification information received wirelessly from the terminal, and selects the selected secondary base station The first identification information of the secondary base station is set to the signal addressed to the secondary base station and transmitted to the relay communication device, and the second of the selected secondary base station A transmitting unit that transmits to the relay transmitter sets a different information on the signal of the terminal addressed.

  One aspect of the present invention is the wireless communication system described above, wherein the transfer path control unit uses the first identification information set in the signal received from the master base station and the system information. The generated first identification information is collated, and when the collation is successful, the signal is transferred to the secondary base station corresponding to the first identification information.

  One aspect of the present invention is the above-described wireless communication system, wherein the destination control unit determines the system information of the secondary base station based on information used for communication between the relay communication device and the secondary base station. Generate.

  One aspect of the present invention is the above-described wireless communication system, in which the relay communication device and the secondary base station are connected by wireless, optical fiber, or logical line.

  One aspect of the present invention is the above-described wireless communication system, wherein the master base station receives wireless quality information between the terminal and the secondary base station of the first identification information.

  One aspect of the present invention is the above-described wireless communication system, wherein the first identification information includes information on a provider of the secondary base station.

  One aspect of the present invention is the relay communication in a wireless communication system including a master base station, one or more secondary base stations, and a relay communication device that relays communication between the master base station and the secondary base station. A destination control unit for notifying the secondary base station of system information used for generating first identification information for identifying a radio access network used for radio communication with the terminal by the secondary base station; A process of notifying the master base station that wirelessly communicates with the terminal second identification information that specifies radio resources that the base station permits use, and a signal received from the master base station are set in the signal A transfer path control unit that performs a process of transferring to the secondary base station according to the first identification information or the second identification information.

  One aspect of the present invention is a communication control method in a wireless communication system including a master base station, one or more secondary base stations, and a relay communication device that relays communication between the master base station and the secondary base station. The relay communication apparatus notifies the secondary base station of system information used for generating first identification information for specifying a radio access network used by the secondary base station for radio communication with the terminal. A notification step; a first identification information generation step in which the secondary base station generates the first identification information based on the system information notified from the relay communication device; and a signal in which the first identification information is set. The first identification information wireless transmission step for transmitting to the terminal by the second identification information for identifying the wireless resource permitted to be used A second identification information notifying step for notifying the master base station via the relay communication device, and the master base station from the secondary base station of the first identification information received from the terminal by radio The secondary base station that communicates with the terminal is selected, the first identification information of the selected secondary base station is set in the signal addressed to the secondary base station, and is transmitted to the relay communication device. A transmitting step of setting the second identification information of the station to the signal addressed to the terminal and transmitting the signal to the relay communication device; and setting the signal received by the relay communication device from the master base station as the signal A transfer step of transferring to the secondary base station according to the first identification information or the second identification information being performed, and the secondary base station Having a radio transmission step of transmitting to the terminal by wireless the signal of the terminal addressed transferred from the relay transmitter.

  According to the present invention, it is possible to reduce the complexity of setting information change between the master base station and the secondary base station.

It is a figure which shows the example of the network structure of the radio | wireless communications system by embodiment. It is a block diagram which shows the structural example of the relay communication apparatus by the embodiment. It is a block diagram which shows the structural example of the relay communication apparatus by the embodiment. It is a block diagram which shows the structural example of the relay communication apparatus by the embodiment. It is a block diagram which shows the structural example of SeNB by the embodiment. It is a block diagram which shows the structural example of SeNB by the embodiment. It is a block diagram which shows the structural example of SeNB by the embodiment. It is a figure which shows the example of a connection of the relay communication apparatus by 1st embodiment, and SeNB. It is a figure which shows the example of the system information table which the relay communication apparatus by the same embodiment memorize | stores. It is a flowchart which shows the example of the system information setting procedure of the relay communication apparatus by the embodiment. It is a flowchart which shows the example of operation | movement after the system information reception of SeNB by the embodiment. It is a sequence diagram which shows the example of the communication procedure of MeNB and relay communication apparatus by the embodiment. It is a flowchart which shows the route control process of the relay communication apparatus by the embodiment. It is a figure which shows the example of the radio | wireless resource information which the transfer path | route control part by the embodiment hold | maintains. It is a figure which shows the example of a connection of the relay communication apparatus by 2nd embodiment, and SeNB. It is a figure which shows the example of the system information table which the relay communication apparatus by the same embodiment memorize | stores. It is a figure which shows the example of a connection of the relay communication apparatus and SeNB by 3rd embodiment. It is a figure which shows the example of the system information table which the relay communication apparatus by the same embodiment memorize | stores. It is a figure which shows the example of the network structure of the conventional radio | wireless communications system.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In this embodiment, the radio communication system performs dual connectivity (DC), and the master base station (MeNB) does not know the IP address of the secondary base station (SeNB) in advance via the relay communication device. The control signal and user data are transferred to the SeNB that is to perform DC.

<Description on Relay Communication Device and SeNB>
FIG. 1 is a diagram illustrating an example of a network configuration of a wireless communication system 100 according to the embodiment. The wireless communication system 100 has a network configuration in which the relay communication device 5 is interposed between the MeNB 1 and N (N is an integer of 1 or more) SeNBs 2. In the figure, a case where N = 3 is shown as an example. The n-th SeNB2 (n is an integer from N to 1) is described as SeNB2-n. MeNB1 and the relay communication apparatus 5 have a known destination in TNL.

  The relay communication device 5 receives a control signal for performing DC and downlink user data after distribution from the MeNB 1 and recognizes it, and transfers it to any of the SeNBs 2-1 to 2-N that are to perform DC It is. The relay communication device 5 is connected to the MeNB 1 via the link 3-1, and is connected to the SeNB 2-n via the link 6-n. X2-IF is used for the link 3-1. In order to perform DC in the configuration shown in the figure, the MeNB 1 transfers the downlink user data after distribution to the SeNBs 2-1 to 2-N of the cell in which the UD 4 exists via the relay communication device 5. Unlike the network configuration illustrated in FIG. 19, the MeNB 1 does not explicitly grasp the TNL destination information of the SeNBs 2-1 to 2-N.

  FIG. 2 is an example of a block diagram showing the configuration of the relay communication device 5, and only functional blocks related to this embodiment are extracted and shown. The relay communication device 5 includes an X2-IF communication function unit 501, a relay communication function unit 502, a destination control unit 503, and a transfer path control unit 504. The relay communication device 5 is connected to the MeNB 1 by the X2-IF communication function unit 501 and connected to the SeNB 2 by the relay communication function unit 502. After establishing communication with the SeNB 2, the destination control unit 503 determines identification information that the SeNB 2 transmits to the UE 4 under its control.

  The relay communication device 5 transfers the control signal received from the MeNB 1 and the downlink user data after distribution to an appropriate SeNB 2. Therefore, the transfer path control unit 504 has a function of collating the identification information of the SeNB 2 set in the control signal received from the MeNB 1 and controlling the transfer path of the control signal and downlink user data.

Instead of the relay communication device 5 shown in FIG. 2, the relay communication device 5a having the configuration shown in FIG. 3 or the relay communication device 5b shown in FIG. 4 can be used.
FIG. 3 is an example of a block diagram showing the configuration of the relay communication device 5a, and only functional blocks related to the present embodiment are extracted and shown. The relay communication apparatus 5a shown in the figure is different from the relay communication apparatus 5 shown in FIG. 2 in that the destination control unit 503 and the transfer path control unit 504 directly transmit and receive data. The transfer path control unit 504 receives and stores information set by the destination control unit 503.

  FIG. 4 is an example of a block diagram showing the configuration of the relay communication device 5b, and only functional blocks related to the present embodiment are extracted and shown. The relay communication device 5b shown in the figure is different from the relay communication device 5 shown in FIG. 2 in that a signal separation unit 505 is provided between the X2-IF communication function unit 501 and the transfer path control unit 504. The signal separation unit 505 separates the control signal and the data signal received from the MeNB 1 and outputs them to the transfer path control unit 504 at the subsequent stage. As a result, the relay communication device 5b separates the control signal and the data signal, and performs destination control and transfer path control on the separated signals. The relay communication device 5b may be configured to include a signal separation unit 505 between the X2-IF communication function unit 501 and the transfer path control unit 504 of the relay communication device 5a illustrated in FIG.

  FIG. 5 is an example of a block diagram showing the configuration of the SeNB 2, and only functional blocks related to the present embodiment are extracted and shown. The SeNB 2 includes a relay communication function unit 201, a radio access communication function unit 202, and a system information recording unit 203. The SeNB 2 is connected to the relay communication device 5 by the relay communication function unit 201 and wirelessly connected to the subordinate UE 4 by the radio access communication function unit 202. The system information recording unit 203 records identification information of a radio access network used when the radio access communication function unit 202 communicates with the UE 4. The radio access communication function unit 202 has a function of generating system information (for example, an RRC layer System information block type message or a PHY layer synchronization signal) to be transmitted to the UE 4 according to the identification information recorded in the system information recording unit 203. Have.

Instead of SeNB2 shown in FIG. 5, SeNB 2a having the configuration shown in FIG. 6 or SeNB 2b shown in FIG. 7 can be used.
FIG. 6 is an example of a block diagram showing the configuration of the SeNB 2a, and only functional blocks related to this embodiment are extracted and shown. The SeNB 2a shown in the figure is different from the SeNB 2 shown in FIG. 5 in that the radio access communication function unit 202 is not connected to the system information recording unit 203. The wireless access communication function unit 202 transmits / receives data to / from the system information recording unit 203 via the relay communication function unit 201.

  FIG. 7 is an example of a block diagram showing the configuration of the SeNB 2b, and only functional blocks related to the present embodiment are extracted and shown. The SeNB 2b shown in the figure is different from the SeNB 2 shown in FIG. 5 in that the relay communication function unit 201 is not connected to the system information recording unit 203. The relay communication function unit 201 transmits / receives data to / from the system information recording unit 203 via the wireless access communication function unit 202.

  In FIG. 1, the connection between the relay communication device 5 and SeNBs 2-1 to 2-N is described as links 6-1 to 6-N. The links 6-1 to 6-N do not necessarily have to be physically independent communication paths as long as the connection relationship between the relay communication device 5 and each SeNB 2 can be distinguished. The connection method of the links 6-1 to 6-N is not particularly limited to wired or wireless. The links 6-1 to 6-N may be a dedicated line connection method, or may be a shared line (for example, multiple access by radio frequency or optical wavelength) connection method.

  UE4 shown in FIG. 1 is a terminal device having a DC communication function. The UE 4 is in a state (RRC_CONNECTED) where the connection with the cell of the MeNB 1 is established in the RRC (Radio Resource Control) layer. The UE 4 can receive radio waves from the cells of the SeNBs 2-1 to 2-N, and can constantly measure the quality of radio access communication with the SeNBs 2-1 to 2-N. UE4 can report the measured quality with respect to MeNB1 using RRC messages, such as MeasurementReport.

<First embodiment>
In the first embodiment, the link connection between the relay communication device 5 and each SeNB 2 is wireless.
FIG. 8 is a diagram illustrating a connection example between the relay communication device 5 and the plurality of SeNBs 2 according to the present embodiment. As shown in the figure, links 6-1 to 6-N between the relay communication device 5 and SeNBs 2-1 to 2-N (N = 3 in the figure) are wireless communication communication paths. In addition to the configuration shown in FIG. 2, 3, or 4, the relay communication device 5 shown in FIG. And an interface for wireless communication. The SeNBs 2-1 to 2-N may include an interface for performing wireless communication similar to the relay communication device 5 in addition to the configuration of the SeNB 2b illustrated in FIG.

  FIG. 9 is a diagram illustrating an example of a system information table stored in the destination control unit 503 of the relay communication device 5. The system information table includes data in which the SeNB number of SeNB2, communication information indicating a wireless connection status with SeNB2, and system information assigned to SeNB2 are associated with each other. The SeNB number is information for individually identifying SeNB2. The wireless connection status includes information on the wireless center frequency, bandwidth number, and antenna number. The system information is individual information for each SeNB2. The system information includes first system information and second system information that the SeNB 2 delivers to the UE 4.

  The relay communication function unit 502 of the relay communication device 5 grasps the connection status in the relay section of the links 6-1 to 6-N between the SeNBs 2-1 to 2-N. The relay communication device 5 communicates wirelessly with the SeNB 2 that is newly added to the relay communication function unit 502. Therefore, the relay communication function unit 502 shares at least a part of communication information with the SeNB 2 among the radio center frequency, the bandwidth number, the antenna number, and the like as illustrated in the example of FIG. . Here, the communication connection agreement method is not specifically specified, and an arbitrary method may be used. However, the relay communication apparatus 5 shall detect the result of communication connection with SeNB2, and shall perform required control with respect to SeNB2. A method in which the relay communication device 5 controls the SeNB 2 will be described below.

  The destination control unit 503 of the relay communication device 5 acquires information (communication information) related to the communication connection with the new SeNB 2 from the relay communication function unit 502. The destination control unit 503 uses the acquired communication information to set the system information used when the new SeNB 2 communicates with the UE 4 via the radio access network so as not to overlap with other SeNB 2. The destination control unit 503 associates the SeNB number, communication information, and system information of the new SeNB 2 and adds them to the system information table (FIG. 9). The destination control unit 503 distributes the system information set in the new SeNB 2 to the new SeNB 2 via the relay communication function unit 502.

  The relay communication function unit 502 or the destination control unit 503 of the relay communication device 5 obtains a PLMN-ID that is identification information of the network operator to which the SeNB2 belongs after the communication connection with the new SeNB2, and transfers the path control unit Save to 504. Further, the relay communication function unit 502 or the destination control unit 503 also saves the system information set to be used by the new SeNB 2 in the transfer route control unit 504.

FIG. 10 is a flowchart illustrating an example of a procedure for setting system information to be used by the newly connected SeNB 2 by the relay communication device 5.
The relay communication function unit 502 of the relay communication device 5 grasps connection information with the newly connected SeNB 2 (step S101). For example, as illustrated in FIG. 9, the destination control unit 503 stores communication information such as a radio center frequency, a bandwidth number, or an antenna number in the system information table, and further sets system information to be used by the SeNB 2. The destination control unit 503 sets the system information used by the SeNB 2 based on the connection information grasped by the relay communication function unit 502 so as not to overlap in different SeNBs 2 (step S102).

  For example, as illustrated in the example of FIG. 9, when adding the SeNB 2 with the SeNB number 4, the destination control unit 503 first delivers the SeNB 2 to the UE 4 based on the center frequency f1 Hz used for connection with the SeNB 2. Set system information to 1. That is, at the center frequency fi, the first system information is i. Next, since the bandwidth number connected to SeNB2 is BW1 and the antenna number is ANT2, the destination control unit 503 sets the second system information that SeNB2 delivers to UE4 based on these. That is, when the bandwidth number is BWj and the antenna number ANTk, the second system information is jk. As described above, the destination control unit 503 sets the system information including the first system information and the second system information so that the SeNBs 2 do not overlap each other, and distributes the system information to the SeNB 2 via the relay communication function unit 502 ( Step S103).

  Without being limited to the above procedure, if there is a setting or management method in the relay communication apparatus 5 so that system information is not duplicated for different SeNBs 2, that method may be used. In the above description, a method for setting system information in SeNB 2 using a radio frequency, a bandwidth, and an antenna number has been described. In addition, if there is information by which the relay communication device 5 can uniquely identify the SeNB 2 on the wireless physical line, for example, information such as a time slot, a coding type, and transmission power used during communication may be used.

[Identification information setting method of radio access network in SeNB2]
FIG. 11 is a flowchart illustrating an example of an operation after the new SeNB 2 receives the above-described system information from the relay communication device 5. After receiving the system information from the relay communication device 5 (Step S201), the SeNB 2 updates the first system information and the second system information held by the system information recording unit 203 with the received system information (Step S202). ). Thereafter, the system information recording unit 203 generates identification information regarding the radio access network to be transmitted to the UE 4 using the updated first system information and second system information (step S203). The radio access communication function unit 202 sets the identification information generated in step S203 when transmitting radio toward the UE 4 (step S204).

  As identification information regarding the radio access network transmitted from the SeNB 2 to the UE 4, there are a synchronization signal Primary synchronization signal and a Secondary synchronization signal in the PHY layer of the eNB defined in the standard (reference document 1 “3GPP TS 36.211 version 12.8.0”). (See Release 12, January 2016, p.111-114). The eNB can select a maximum of 504 combinations of non-overlapping synchronization signals from three types of primary synchronization signals and 168 types of secondary synchronization signals.

  In step S203, the system information recording unit 203 of the SeNB 2 associates the primary synchronization signal with the secondary synchronization signal using the first system information and the second system information included in the system information received from the relay communication device 5. Then, a combination of synchronization signals that does not overlap is generated. For example, since the first system information used by the SeNB 2 with the SeNB number 4 shown in FIG. 9 is 1, in step S204, the radio access communication function unit 202 transmits the first primary synchronization signal to the UE 4. Further, since the second system information is 12, in step S204, the radio access communication function unit 202 transmits the 12th secondary synchronization signal to the UE4.

  In addition to the above processing, the SeNB 2 further transmits other identification information related to the radio access network to the UE 4 via the radio access communication function unit 202. Reference information 2 “3GPP TS 36.331 version 13.5.0 Release 13, April 2017” p.263 describes Systeminformationblocktype1 Message in the RRC layer. In the PLMN-IDentityList of the SystemInformationBlockType1 Message, identification information PLMN-ID for determining the provider to which the SeNB 2 belongs is described. The identification information PLMN-ID is assigned to the provider so as not to overlap. The UE 4 can determine which provider's SeNB2 radio access network information has been received with reference to the identification information PLMN-ID.

[Description of operation in which UE4 reports information on radio access network of SeNB2 to MeNB1]
UE4 can calculate the physical layer cell ID associated with the combination by using the synchronization signal Primary synchronization signal and Secondary synchronization signal received from SeNB2, and measure the radio access communication quality with SeNB2 Is possible. As shown in p.148-151 of Reference Document 2, UE4 sets MeasResults in the measurement report message of the RRC layer and transmits it to MeNB1 by setting the measurement result of the radio access communication quality with SeNB2, to MeNB1. Information related to radio access communication quality with each SeNB 2 is reported. Specifically, the UE 4 describes the PLMN-ID of the SeNB 2 in the PLMN-IDentityList of MeasResults, and describes the physical layer cell ID in the PhysCellId of MeasResults.

[Description of operation in which relay communication device 5 reports radio resources of radio access network to MeNB 1]
The relay communication device 5 establishes a connection with the new SeNB2, and then transmits the first system information and the second system information to the target SeNB2 as in step S103 above, and then wirelessly accesses the MeNB1. Report the addition of network resources.

  As an example of the reporting method, there is, for example, the method shown in p.27, 64, 107-109 of Reference 3 “3GPP TS 36.423 version 13.7.0 Release 13, August 2017”. In this method, the transfer path control unit 504 of the relay communication device 5 sets the PLMN-ID related to the added SeNB2 in the IE of the Global eNB ID of the X2 SETUP REQUEST Message, and sets the physical layer of the SeNB2 in the IE of PCI. Set cell ID and report to MeNB1.

  MeNB1 can judge that the resource of the radio access network was added by connection with new SeNB2 based on the report from such a relay communication apparatus 5. FIG. The MeNB 1 can determine which radio resource exists in each relay communication device 5 even when a plurality of relay communication devices 5 are connected simultaneously.

  When SeNB2 is removed from the subordinate of the relay communication device 5, the relay communication device 5 deletes the removed SeNB2 and the system information assigned to the SeNB2 from the management table shown in FIG. As described in p.30-31 and p.66-69 of No. 3, it is possible to notify the MeNB 1 of the change of the radio resource.

[Description of Communication Method Between MeNB 1 and Relay Communication Device 5]
MeNB1 shown in FIG. 1 selects SeNB2 which performs DC, after receiving the information regarding the radio | wireless access communication quality with each of several SeNB2 from UE4. MeNB1 performs this selection according to the information of the radio | wireless resource in the radio | wireless access network received from the relay communication apparatus 5, and the user data amount of the downlink which needs the transfer to UE4. The MeNB 1 secures the radio resource of the selected SeNB 2 via the relay communication device 5. A sequence example of this communication procedure is shown in FIG.

[Identification and Transfer of Control Signal in Relay Communication Device 5]
FIG. 12 is a sequence diagram illustrating an example of a communication procedure between the MeNB 1 and the relay communication device 5. UE4 transmits the radio | wireless reception and measurement result from each SeNB2 to MeNB1 by MeasurementReport Message (step S301). The UE 4 also sets the PLMN-ID and physical layer cell ID information of the SeNB 2 in this Measurement Report Message. MeNB1 transmits SeNB Addition Request Message addressed to SeNB2 that can be the target of DC to relay communication device 5 as shown in p.103-104 of Non-Patent Document 1 (step S302). The contents of SeNB Addition Request Message are as shown in p.83 of Reference 3 and p.571-574 of Reference 2. MeNB1 sets information of PLMN-ID and physical layer cell ID in this SeNB Addition Request Message.

  When the transfer path control unit 504 of the relay communication device 5 receives the SeNB Addition Request Message transmitted from the MeNB 1 in step S302, the transfer path control unit 504 performs path control processing to transfer the received Message to the destination SeNB 2. The transfer path control unit 504 extracts information for performing path control from the received signal from the MeNB 1 and transfers the received signal to the SeNB 2 based on the extracted information.

  FIG. 13 is a flowchart showing route control processing in the transfer route control unit 504 of the relay communication device 5. First, the transfer path control unit 504 extracts information on the PLMN-ID and the PhysCellId included in the SCG-ConfigInfo from the SeNB Addition Request Message input from the X2-IF communication function unit 501 (step S401). . In PhysCellId, the physical layer cell ID set by MeNB1 is described. The transfer path control unit 504 confirms whether the same information as the extracted PLMN-ID is held in the own function unit. When the transfer path control unit 504 determines that the same PLMN-ID information is held, the PhysCellId is calculated and extracted by the same method as the UE 4 using the first system information and the second system information. It is confirmed whether or not it matches the PhysCellId (step S402).

  When it is determined that the transfer path control unit 504 has the PLMN-ID extracted in step S401 and the calculated PhysCellId matches the extracted PhysCellId (step S402: YES), the extracted information matches. It is determined that the SeNB 2 exists under the relay communication device 5. The transfer path control unit 504 transfers the SeNB Addition Request Message to the SeNB 2 corresponding to the extracted information (PLMN-ID and PhysCellId) via the relay communication function unit 502 (step S403 in FIG. 13 and step S303 in FIG. 12). ).

  When the transfer path control unit 504 determines that the PLMN-ID extracted in step S402 is not held or the calculated PhysCellId does not match the extracted PhysCellId (step S402: NO), It is determined that SeNB2 does not exist under the control. In this case, the transfer path control unit 504 generates a SeNB Addition Request Reject Message that is a control failure response, and transmits it to the MeNB 1 (step S404).

  The radio access communication function unit 202 of the SeNB 2 that has received the SeNB Addition Request Message transferred by the relay communication device 5 in step S303 in FIG. 12 determines whether the radio resource requested from the MeNB 1 can be provided after receiving the message. If the radio access communication function unit 202 of the SeNB 2 determines that it can be provided, the radio access communication function unit 202 transmits a SeNB Addition Request Acknowledge Message to the relay communication device 5 via the relay communication function unit 201 and notifies the MeNB 1 of permission (step S304). In the SeNB Addition Request Acknowledge Message, an E-RAB ID is set as information indicating a radio resource permitted to be used. The E-RAB ID is information that identifies a radio access bearer (E-RAB).

  When the transfer path control unit 504 of the relay communication device 5 receives the SeNB Addition Request Acknowledge Message from the SeNB 2, it reads the permitted E-RAB ID from the Message. The transfer path control unit 504 records the SeNB number and the read E-RAB ID in association with each other (step S305).

  FIG. 14 is a diagram illustrating an example of the radio resource information held by the transfer path control unit 504. As shown in the figure, the radio resource information is a table in which the SeNB number is associated with the bearer ID permitted in the SeNB 2 of the SeNB number. An E-RAB ID is set in the bearer ID of the radio resource information.

  As illustrated in FIG. 12, the transfer path control unit 504 transfers the SeNB Addition Request Acknowledge Message received from the SeNB 2 to the MeNB 1 after recording the E-RAB ID (step S306). The MeNB 1 performs RRC connection reconfiguration for the subordinate UE 4 in accordance with the content of the SeNB Addition Request Acknowledge Message received from the relay communication device 5, and causes the UE 4 to add radio resources that can be used by the SeNB 2. After completing the radio resource addition in UE4, MeNB1 transmits SeNB Reconfiguration Complete Message to relay communication apparatus 5 (step S307).

  The relay communication device 5 transfers the SeNB Reconfiguration Complete Message to the target SeNB 2 by the method shown in FIG. 13 in the same manner as above (step S308). SeNB2 which performs DC performs the procedure of L1 / L2 Random Access in the area of radio | wireless access communication according to a standard specification between UE4 which performs DC, after receiving SeNB Reconfiguration Complete Message (step S309). When this procedure is completed, the SeNB 2 that is the DC target can communicate with the UE 4.

  There are other control signals to perform DC. When other control signals include PLMN-ID and SCG-ConfigInfo information, it is possible to add and change radio resources for the UE 4 by the same procedure as described above.

  After the above steps S301 to S309 are executed, the MeNB 1 transmits an SN Status Transfer Message, and the relay communication device 5 receives it (step S310). The SN Status Transfer Message includes an E-RAB ID permitted by MeNB1 to SeNB2. The transfer path control unit 504 of the relay communication device 5 recognizes the E-RAB ID in the SN Status Transfer Message, and transfers it to the SeNB 2 associated in step S305 (step S311).

[Identification and transfer of user data in relay communication devices]
MeNB1 divides | segments the downlink user data addressed to UE4 into the user data transmitted from an own apparatus, and the user data transmitted from SeNB2. MeNB1 sets E-RAB ID to the user data transmitted from SeNB2, and transmits it to the relay communication apparatus 5. When the relay communication device 5 receives the downlink user data from the MeNB 1, the transfer path control unit 504 confirms the E-RAB ID included in the header of the user data, and similarly to the above-described SN Status Transfer Message, The user data is transferred to the target SeNB2 that performs DC (steps S312 to S313). The SeNB 2 transmits the downlink user data transferred from the relay communication device 5 to the UE 4 using the radio resource of the E-RAB ID. On the other hand, MeNB1 transmits the downlink user data transmitted from its own device to UE4 by radio.

<Second Embodiment>
A second embodiment of the present invention will be described. FIG. 15 is a diagram illustrating a connection example between the relay communication device 5 and the plurality of SeNBs 2 according to the present embodiment. The entire network configuration of the MeNB 1, the relay communication device 5, and the SeNBs 2-1 to 2-N (N = 3 in the figure) in the wireless communication system of the present embodiment is the same as that of the wireless communication system 100 shown in FIG. . However, the connection configuration between the relay communication device 5 and the SeNBs 2-1 to 2-N is a one-to-many connection using an optical fiber as illustrated in FIG. For this connection, for example, a PON (Passive Optical Network) is used. Hereinafter, the difference from the first embodiment will be mainly described.

  FIG. 16 is a diagram illustrating an example of a system information table stored in the relay communication device 5 according to the embodiment. The relay communication device 5 according to the present embodiment generates and holds the system information table shown in FIG. 16 instead of the system information table shown in FIG. The SeNB number, the first system information, and the second system information set in the system information table shown in FIG. 16 are the same as the system information table shown in FIG.

  Since the relay communication function unit 502 of the relay communication device 5 communicates with the newly added SeNB 2 via an optical fiber, the communication information such as the wavelength of light and the time slot position used during communication as shown in FIG. Share and agree on a communication connection. This communication information shared with SeNB2 is set in the system information table shown in FIG. In the present embodiment, a specific communication connection agreement method is not specified, and an arbitrary method may be used.

In the second embodiment, system information to be used by the SeNB 2 is set by the same method as in the first embodiment. This setting procedure will be described with reference to FIGS.
The relay communication function unit 502 of the relay communication device 5 grasps connection information with the SeNB 2 (step S101). For example, as illustrated in FIG. 16, the destination control unit 503 stores communication information such as a wavelength number and a time slot number in the system information table, and further sets system information to be used by the SeNB 2. The destination control unit 503 sets the system information to be used so as not to overlap in different SeNBs 2 (step S102).

  For example, as illustrated in the example of FIG. 16, when adding the SeNB 2 with the SeNB number 3, the destination control unit 503 first distributes the SeNB 2 to the UE 4 based on the wavelength W1 used for connection with the SeNB 2. Set system information to 1. Next, the destination control unit 503 sets 26 as the second system information that the SeNB 2 distributes to the UE 4 based on the time slot T <b> 26 used for connection with the SeNB 2. In this way, the destination control unit 503 sets the system information including the first system information and the second system information set so as not to overlap between the SeNBs 2, and the SeNB 2 via the relay communication function unit 502. (Step S103).

  Note that the method is not limited to the above procedure, and any method may be used in the relay communication device 5 as long as there is a setting or management method that does not cause system information to be duplicated for different SeNBs 2. In the above description, the method for setting the system information in the SeNB 2 using the wavelength and the time slot number has been described. In addition, if there is information by which the relay communication device 5 can uniquely identify the SeNB 2 on a wired physical line, for example, information such as an encoding type and transmission power used at the time of communication may be used.

[Identification information setting method of radio access network in SeNB2]
The radio access network identification information setting method in SeNB2 and the series of operations in which the set identification information reaches the relay communication device 5 via UE4 and MeNB1 are the same in the second embodiment and the first embodiment. Therefore, detailed description is omitted.

<Third embodiment>
A third embodiment of the present invention will be described. FIG. 17 is a diagram illustrating a connection example between the relay communication device 5 and the plurality of SeNBs 2 according to the present embodiment. The entire network configuration of the MeNB 1, the relay communication device 5, and the SeNBs 2-1 to 2-N (N = 3 in the figure) in the wireless communication system of the present embodiment is the same as that of the wireless communication system 100 shown in FIG. . However, as illustrated in FIG. 17, the relay communication device 5 and the SeNBs 2-1 to 2-N are connected by a layer 2 network. That is, the connection between the relay communication device 5 and the SeNBs 2-1 to 2-N is a one-to-many connection using a logical line with a VLAN tag. Hereinafter, the difference from the first embodiment will be mainly described.

  FIG. 18 is a diagram illustrating an example of a system information table stored in the relay communication device 5 according to the embodiment. The relay communication device 5 according to the present embodiment generates and holds the system information table shown in FIG. 18 instead of the system information table shown in FIG. The SeNB number, the first system information, and the second system information set in the system information table shown in FIG. 18 are the same as the system information table shown in FIG.

  Since the relay communication function unit 502 of the relay communication device 5 communicates with the newly added SeNB 2 via a logical line, a connection port and a VLAN tag for communication under the connection port as shown in FIG. Communication information is shared with SeNB2 and communication connection is agreed. This communication information shared with SeNB2 is set in the system information table shown in FIG. In the present embodiment, a specific communication connection agreement method is not specified, and an arbitrary method may be used.

In the third embodiment, system information to be used by the SeNB 2 is set by the same method as in the first embodiment. This setting procedure will be described with reference to FIGS.
The relay communication function unit 502 of the relay communication device 5 grasps connection information with the SeNB 2 (step S101). For example, as illustrated in FIG. 18, the destination control unit 503 stores communication information such as a connection port number and a VLAN tag number in the system information table, and further sets system information to be used by the SeNB 2. The destination control unit 503 sets the system information to be used so as not to overlap in different SeNBs 2 (step S102).

  For example, as illustrated in the example of FIG. 18, when adding the SeNB 2 with the SeNB number 3, the destination control unit 503 first distributes the SeNB 2 to the UE 4 based on the port P2 used for connection with the SeNB 2. Set system information to 2. Next, the destination control unit 503 sets 10 as the second system information that the SeNB 2 delivers to the UE 4 based on the VLAN tag 10 used for connection with the SeNB 2. As described above, the destination control unit 503 sets the system information including the first system information and the second system information set so as not to overlap between the SeNBs 2, and the relay communication function unit 502 Deliver to SeNB2 (step S103).

  Note that the method is not limited to the above procedure, and any method may be used in the relay communication device 5 as long as there is a setting or management method that does not cause system information to be duplicated for different SeNBs 2. In the above description, the method for setting the system information in the SeNB 2 using the connection port number and the VLAN tag number has been described. In addition, if there is information that can uniquely identify the relay communication device 5 and the SeNB 2 on the logical line, the identifier information may be used.

[Identification information setting method of radio access network in SeNB2]
The identification information setting method of the radio access network in SeNB2 and the series of operations in which the set identification information reaches the relay communication device 5 via UE4 and MeNB1 are the same in the third embodiment and the first embodiment. Therefore, detailed description is omitted.

<Fourth embodiment>
A fourth embodiment of the present invention will be described. Below, the difference of 4th embodiment and 1st-3rd embodiment is described.

[Identification information setting method of radio access network in SeNB2]
In the present embodiment, a method will be described in which the SeNB 2 generates a CSG-ID based on the system information received from the relay communication device 5. The CSG-ID is 28-bit identification information, described in SYSTEMINFORMATIONBLOCKTYPE1 in the RRC layer, and can be transmitted by the SeNB 2 to the UE 4 in the coverage.

  For example, in the system information shown in FIG. 9, the first system information that SeNB 2 with SeNB number 1 delivers to UE 4 is 0, and the second system information is 11. In this case, it is possible to assign 0 as the first digit starting from the left of the CSG-ID to be generated and 11 as the second and third digits. As described above, the system information recording unit 203 of the SeNB 2 generates a CSG-ID different from that of the other SeNB 2 and transmits the CSG-ID from the radio access communication function unit 202 to the UE 4 by radio.

[Description of operation in which UE4 reports information on radio access network of SeNB2 to MeNB1]
UE4 sets the measurement result of the radio access communication quality with SeNB2 including the received PHY layer signal power and CSG-ID described in SYSTEMINFORMATIONBLOCKTYPE1 of RRC layer in MeasResults of MeasurementReport Message of RRC layer, and MeNB1 Send to. Thereby, UE4 reports the information regarding the radio | wireless access communication quality with the SeNB2 to MeNB1.

[Description of operation in which relay communication device 5 reports radio resources of radio access network to MeNB 1]
The relay communication device 5 establishes a connection with the new SeNB 2 and then transmits the first system information and the second system information to the target SeNB 2 as in Step S103 described above, and then wirelessly accesses the MeNB 1 Report the addition of network resources. As an example of this reporting method, for example, the method shown in p.27, 64, 107-109 of Reference 3 is used to report to MeNB1 by X2 SETUP REQUEST Message. That is, the transfer path control unit 504 of the relay communication device 5 sets the PLMN-ID and CSG-ID related to the added SeNB2 in the X2 SETUP REQUEST Message, and transmits it to the MeNB1. PLMN-ID is set to IE of Global eNB ID.

  The MeNB 1 can recognize that the resource of the radio access network has been added by the connection with the new SeNB 2 based on the report from the relay communication device 5. The MeNB 1 can determine which radio resource exists in each relay communication device 5 even when a plurality of relay communication devices 5 are connected simultaneously.

  In addition, when SeNB2 is removed from subordinate of the relay communication device 5, the relay communication device 5 deletes the target SeNB2 and the system information assigned to the SeNB2 from the management table illustrated in FIG. As in p.30-31 and 66-69, it is possible to notify the MeNB1 of the change of the radio resource.

[Description of Communication Method Between MeNB 1 and Relay Communication Device 5]
The MeNB 1 illustrated in FIG. 1 receives information on the radio access communication quality with each of the SeNBs 2-1 to 2-N from the UE 4, and then transmits information on the radio resource in the radio access network received from the relay communication device 5 to the UE 4. The SeNB 2 that performs DC is selected according to the required amount of user data. The MeNB 1 secures the radio resource of the selected SeNB 2 via the relay communication device 5.

  In order to secure radio resources of SeNB2, MeNB1 describes the CSG-ID of SeNB2 to be DC as the IE of Spare of SCG-ConfigInfo in the SeNB Addition Request Message transmitted in step S302 of FIG. Transmit to device 5. The relay communication device 5 transfers a control signal necessary for the subordinate SeNB 2 based on such CSG-ID.

  When the transfer path control unit 504 of the relay communication device 5 receives the permission notification of the SeNB Addition Request Acknowledgment Message from the DC target SeNB2 in step S304 of FIG. 12, the information of the corresponding E-RAB number and CSG-ID is received. Hold. Thereafter, the transfer path control unit 504 of the relay communication device 5 transfers the Addition Request Acknowledgment Message to the MeNB 1.

  Next, the MeNB 1 transfers the user data to the relay communication device 5. At that time, the MeNB 1 describes the E-RAB number in the user data. For this reason, the transfer path control unit 504 of the relay communication device 5 specifies the SeNB 2 that is the DC target from the association relationship between the E-RAB number and the CSG-ID of the subordinate SeNB 2, and transfers user data.

  According to the present embodiment, the control signal necessary for MeNB1 and SeNB2 to perform downlink carrier aggregation with respect to UE4 even if there is no connection / link maintenance in the IP layer between MeNB1 and multiple SeNB2. In addition, user traffic can be transferred via the relay communication device. Specifically, the relay communication device 5 extracts a control signal of a mobile communication system or a message or header information originally included in user traffic, and provides a route control method at the time of transfer to a plurality of SeNBs 2.

  According to the embodiment described above, the wireless communication system performs communication between a master base station that wirelessly communicates with a terminal, one or more secondary base stations that can wirelessly communicate with the terminal, and the master base station and the secondary base station. A relay communication device for relaying. The relay communication device and the secondary base station are connected by, for example, radio, optical fiber, or logical line.

  The relay communication device includes a destination control unit and a transfer path control unit. The destination control unit notifies the secondary base station of system information used for generating first identification information that specifies a radio access network used by the secondary base station for radio communication with the terminal. For example, the destination control unit generates system information of the secondary base station based on information used for communication between the relay communication device and the secondary base station. The transfer path control unit notifies the master base station of second identification information that identifies radio resources that the secondary base station permits use of. The transfer path control unit transfers the signal received from the master base station to the secondary base station corresponding to the first identification information or the second identification information set in the signal. At this time, the transfer path control unit collates the first identification information set in the signal received from the master base station with the first identification information generated using the system information. You may transfer a signal to the secondary base station according to one identification information.

  The secondary base station includes a first identification information generation unit, a second identification information notification process, and a radio access communication function unit. The first identification information generation unit generates first identification information based on the system information notified from the relay communication device. The first identification information generation unit is, for example, the system information recording unit 203. The second identification information notification unit notifies the master base station of the second identification information of the radio resource permitted to be used via the relay communication device. The second identification information notification unit is, for example, the wireless access communication function unit 202. The wireless access communication function unit wirelessly transmits a signal set with the first identification information and a signal addressed to the terminal transferred from the relay communication device to the terminal. The terminal wirelessly receives a signal in which the first identification information is set from each secondary base station, and information indicating a measurement result of the wireless quality between the first identification information and the secondary base station of the first identification information; Is transmitted to the master base station by radio.

  The transmission part of a master base station selects the secondary base station which communicates with a terminal from the secondary base stations of the 1st identification information received from the terminal. The transmission unit sets the first identification information of the secondary base station in the signal addressed to the selected secondary base station, and transmits the first identification information to the relay communication device. Moreover, a transmission part sets the 2nd identification information of the selected secondary base station to the signal addressed to a terminal, and transmits to a relay communication apparatus.

  As the first identification information, for example, Physical Cell ID or CSG-ID and PLMN-ID can be used. Since the primary synchronization signal and the secondary synchronization signal generated from the system information can be converted into a physical cell ID, these can also be regarded as the first identification information. For example, an E-RAB ID can be used as the second identification information.

  Note that all or a part of each function of the MeNB1, SeNB2, 2a, 2b and the relay communication devices 5, 5a, 5b is ASIC (Application Specific Integrated Circuit), PLD (Programmable Logic Device), FPGA (Field Programmable Gate). Array) or the like may be used. The MeNB1, SeNB2, 2a, 2b and the relay communication devices 5, 5a, 5b include a CPU (Central Processing Unit) connected via a bus, a memory, an auxiliary storage device, and the like, and the functions described above by executing a program It functions as a device provided with. The program may be recorded on a computer-readable recording medium. The computer-readable recording medium is, for example, a portable medium such as a flexible disk, a magneto-optical disk, a ROM, a CD-ROM, or a storage device such as a hard disk built in the computer system. The program may be transmitted via a telecommunication line.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and includes designs and the like that do not depart from the gist of the present invention.

1 ... MeNB, 2-1 to 2-3, 2, 2a, 2b ... SeNB, 3-1 ... link, 4 ... UE, 5, 5a, 5b ... relay communication device, 6-1 to 6-3 ... link, DESCRIPTION OF SYMBOLS 100 ... Wireless communication system, 201 ... Relay communication function part, 202 ... Wireless access communication function part, 203 ... System information recording part, 501 ... X2-IF communication function part, 502 ... Relay communication function part, 503 ... Destination control part, 504 ... Transfer path control unit, 505 ... Signal separation unit

Claims (8)

A wireless communication system having a master base station, one or more secondary base stations, and a relay communication device that relays communication between the master base station and the secondary base station,
The relay communication device is
A destination control unit for notifying the secondary base station of system information used to generate first identification information for specifying a radio access network used by the secondary base station for radio communication with a terminal;
A process of notifying the master base station of second identification information for specifying a radio resource permitted to be used by the secondary base station, and a signal received from the master base station, the first identification set in the signal A transfer path control unit that performs processing to transfer to the secondary base station according to the information or the second identification information,
The secondary base station is
A first identification information generating unit that generates the first identification information based on the system information notified from the relay communication device;
A second identification information notification unit for notifying the master base station of the second identification information of the radio resource permitted to be used, via the relay communication device;
A radio access communication function unit that wirelessly transmits the signal set to the first identification information and the signal addressed to the terminal transferred from the relay communication device to the terminal;
The master base station is
The secondary base station that communicates with the terminal is selected from the secondary base stations of the first identification information received wirelessly from the terminal, and the first identification information of the selected secondary base station is selected as the secondary base station A transmission unit configured to set the signal addressed to the relay communication apparatus, transmit the second identification information of the selected secondary base station to the signal addressed to the terminal, and transmit the signal to the relay communication apparatus; ,
Wireless communication system. When the transfer path control unit collates the first identification information set in the signal received from the master base station with the first identification information generated using the system information, and the collation is successful To transfer the signal to the secondary base station according to the first identification information,
The wireless communication system according to claim 1. The destination control unit generates the system information of the secondary base station based on information used for communication between the relay communication device and the secondary base station.
The radio | wireless communications system of Claim 1 or Claim 2. The relay communication device and the secondary base station are connected by radio, optical fiber, or logical line,
The radio | wireless communications system as described in any one of Claims 1-3. The master base station receives information on radio quality between the terminal and the secondary base station of the first identification information,
The radio | wireless communications system as described in any one of Claims 1-4. The first identification information includes information on an operator of the secondary base station,
The radio | wireless communications system as described in any one of Claims 1-5. The relay communication device in a wireless communication system having a master base station, one or more secondary base stations, and a relay communication device that relays communication between the master base station and the secondary base station,
A destination control unit for notifying the secondary base station of system information used to generate first identification information for specifying a radio access network used by the secondary base station for radio communication with a terminal;
A process of notifying the master base station that wirelessly communicates with the terminal second identification information that specifies radio resources that the secondary base station permits use of, and a signal received from the master base station are set in the signal A transfer path control unit that performs processing to transfer to the secondary base station according to the first identification information or the second identification information,
A relay communication device comprising: A communication control method in a wireless communication system having a master base station, one or more secondary base stations, and a relay communication device that relays communication between the master base station and the secondary base station,
The relay communication device is
A system information notifying step for notifying the secondary base station of system information used for generating first identification information for specifying a radio access network used by the secondary base station for radio communication with a terminal;
The secondary base station is
A first identification information generating step for generating the first identification information based on the system information notified from the relay communication device;
A first identification information wireless transmission step of wirelessly transmitting a signal in which the first identification information is set to the terminal;
A second identification information notification step of notifying the master base station via the relay communication device, second identification information for specifying a radio resource permitted to be used;
The master base station is
The secondary base station that communicates with the terminal is selected from the secondary base stations of the first identification information received wirelessly from the terminal, and the first identification information of the selected secondary base station is selected as the secondary base station A transmission step of setting the signal addressed to the relay communication device and transmitting the second identification information of the selected secondary base station to the signal addressed to the terminal and transmitting to the relay communication device;
The relay communication device is
A transfer step of transferring the signal received from the master base station to the secondary base station according to the first identification information or the second identification information set in the signal;
The secondary base station is
A wireless transmission step of wirelessly transmitting the signal addressed to the terminal transferred from the relay communication device to the terminal;
A communication control method.

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